I helped my son install a new used 302 in his 88 f150. After a long time cranking it finally started. It ran pretty well, but he needs to set the timing.
After a few hours I went out and tried to start it again. No start. However, when you let go of the key, it seems to fire. It doesn't actually run, but it kicks back. OK throw some ideas at me.
I should ad to this. The previous engine had the same issues according to my son. The newly installed engine had the fuel rails and distributor in it.
So distributor is not the same one. He had already replaced the coil with an MSD unit.

 

Timing. Set the timing and you should be good to go.

 

Sounds like the stator (AKA pick up coil) on both engines went south. When you turn the key to START you'll get no voltage signal but when the key is released, it collapses the coil and you get a quick start but then dies.

The stator is under the base plate in the distributor......about 30? bucks......

 

OK I'm back. My son has worked on the truck while I'm at work. I work 2nd shift.
The truck is very hard to start. It will idle good, and accelerate ok when in park. But once in gear it won't accelerate at all. Then it dies. He has changed the distributor with a rebuilt unit that came from the old motor. He has set the timing. This morning I checked fuel pressure at the schrader while cranking. 40psi I put a test light in the coil plug, and I get a good blink when I crank it.

 

What year was the donor engine out of?

I put a '93-'94 engine in my '87 when the 4.9L self destructed. It would barely run on an '87 5.0L computer, but when I tried a borrowed computer from a '94 truck it ran just fine. I'm not certain, but I think there was change in the injectors at one point and that resulted in a change in programming. In my case, I purchased a later model ECM and sold the '87 box to a friend to recoup some of the expense. It was still cheaper than buying a set of early injectors...

If I were you, I'd swap out the injectors for the ones in the original engine and see if that clears things up.

 

Sorry, no change in the injectors during that time period. 1994 was the first year for the Computer Controlled Dwell (CCD) ignition system on Ford trucks. This did trigger a programming and wiring change for the IDM signal as well as a very different Ignition Control Module (ICM).

 

OK I'm updating to this post. After a miserable time, I've still got problems. After consulting with a professional mechanic locally, it was determined the ignition module was bad. He had just worked on a 89 Mercury 302 that had the same symptoms as this truck.
He went through 3 autozone units without any luck. He found O'Reilly's sells the actual
Motorcraft unit $54. His problem was solved. So I pulled the distributor my son had installed, and put back in the one that was with the engine when he bought it. It actually has a generic module on it, but the engine was tagged running when pulled.
Got truck started. It high idled about 30 seconds, then settled down. After about a minute it started to fumble around and slowed till it almost died. Then it decided to run and it kicked back up to a high idle. Then settle down and start same thing all over again. I took it for a drive. It runs and accelerates quite well. No stalling till I got home. I pulled up in the street ready to back in. Shifted into reverse and then turned steering wheel. As soon as I did it stalled. Starts right back up, and then backed in.

Another issue. I want to read the codes. However, my sons dash is missing the cover over all the idiot lights. Which one is the check engine light? I tried to flash the computer with KOEO. I sat in truck and got no blinking of any light at all. I want to find right location so I can change that bulb.

 

I believe you are looking for the yellow Check Engine Light